Grain Storage Calculator
Calculate the capacity of a bin or store in tonnes and bushels.
Please note: Planning figures based on published averages. Soil type, climate, variety, season and local practice all shift these results substantially. Base real decisions on a soil test, local extension guidance and the product label — particularly for fertiliser, lime and any crop protection product, where the label is a legal document.
What the Grain Storage Calculator does
Store capacity is a volume calculation converted to weight by the grain’s bulk density. Bushels are a volume unit, so a bin holds the same number of bushels regardless of crop — but the tonnage varies substantially, because oats occupy far more space per tonne than wheat.
Formula
Cylinder volume = π × (Diameter ÷ 2)² × DepthPeaked cone adds = Floor area × Cone height ÷ 3Tonnes = Volume × Bulk density ÷ 1,000Bushels = Volume ÷ 0.035239 m³
Inputs explained
| Input | Unit | Required | Notes |
|---|---|---|---|
| Store shape | one of 2 options | Yes | — |
| Diameter | m | In some modes | Accepts more than 0. Shown Store shape is Cylindrical bin or silo. |
| Length | m | In some modes | Accepts more than 0. Shown Store shape is Rectangular shed or bay. |
| Width | m | In some modes | Accepts more than 0. Shown Store shape is Rectangular shed or bay. |
| Grain depth | m | Yes | Accepts more than 0. |
| Crop | one of 8 options | Yes | — |
| Cone height above the eave | m | Optional | Accepts 0 or more. Shown Store shape is Cylindrical bin or silo. |
| Grain price per tonne | selected currency | Optional | Accepts 0 or more. |
| Currency | one of 10 options | Optional | — |
How to use it
- Choose Store shape and Crop.
- Enter Grain depth.
- Fill in the remaining inputs the form shows for your choice.
- Optionally add Grain price per tonne.
- Select Calculate.
Worked example
A 6 m diameter bin filled to 8 m with wheat.
- Shape
- Cylindrical
- Diameter
- 6 m
- Depth
- 8 m
- Crop
- Wheat
π × 3² × 8 = 226.2 m³. At 772 kg/m³ that is 174.6 tonnes, or 6,419 bushels.
Reading the result
- "Capacity per metre of depth" lets a partial fill level be checked quickly, without recomputing the whole volume for a bin that is not yet full.
- The "capacity by crop" table shows why comparing bin capacity purely in tonnes is misleading — the same bin holds the same bushels regardless of crop, but the tonnage stored in it depends entirely on what is put in.
Assumptions and limitations
- Bulk density is a single "typical" figure for clean, dry grain — the notes flag that moisture and cleanliness change it, so wetter or trashier grain packs differently and the true tonnage in a physically full bin can differ from this estimate.
- "Grain depth" is treated as the actual fill height reached — it does not itself subtract the headroom the notes recommend leaving, so entering the full bin height rather than a safe fill height overstates usable capacity.
Common mistakes
- Leaving "cone height" at its default of 0 for a peaked bin — that silently omits the cone's extra volume from the total, understating true storage when the actual cone height was never entered.
Frequently asked questions
Why does a bin hold the same bushels but different tonnes?
Because a bushel is a volume, not a weight. The bin holds a fixed number of bushels; how much those weigh depends entirely on the crop.
Should I fill to the top?
No. Leave headroom for aeration and safe access, and expect the grain to settle by a few percent after filling.